Comparison of Clinical Success of Applying a Kind of Fissure Sealant on the Lower Permanent Molar Teeth in Dry and Wet Conditions

Statement of the Problem Fissure sealant therapy is among the most effective methods of preventing dental caries. However, it is lengthy and isolation of the teeth is difficult in this procedure especially in young children. Using new hydrophilic fissure sealant may reduce such problems. Purpose This study aimed to evaluate the clinical success of a hydrophilic fissure sealant on the lower permanent molar teeth in dry and wet conditions. Materials and Method This clinical trial assessed 31 patients (mean age 8.13±1.77 years) who needed fissure sealant therapy on their first or second mandibular permanent molar. Having performed dental prophylaxis, the teeth were etched and rinsed. Then one of the two was randomly selected and sealed with smartseal & loc in isolated and dry conditions; while, the other was wetted on the etched enamel by using a saliva-contaminated micro brush, and was then sealed with the same fissure as the first tooth. Six and 12 months later, two independent observers examined the clinical success of sealant through checking the marginal integrity, marginal discoloration, and anatomical form. Data were analyzed by using SPSS software, version 16. The bivariate Chi-square and Exact Fisher tests were used to compare the clinical success of the two treatment methods. Results There was a high interpersonal reliability between the two examiners (K= 0.713). After 12 months, 90.3% clinical success was observed in dry conditions and 83.9% in wet conditions for smartseal & loc; however, the difference was not statistically significant (p= 0.0707). Conclusion According to the results of this study, it seems that using new hydrophilic fissure sealant can reduce technical sensitivities and consequently decreases the apprehensions on saliva contamination of etched enamel during treatment procedures.


Introduction
Over the two past decades, developments in dentistry, especially introduction and application of fluoride in the form of toothpastes, mouthwashes, and topical fluoride therapy, as well as fluoridation of drinking water have significantly cut down on tooth decay, particularly on proximal and smooth surfaces of the teeth.
Occlusal surfaces of first and second permanent molar teeth are susceptible to decay in young patients and also have lower fluoride absorbing in comparison with smooth surfaces. Although occlusal surfaces constitute only 13% of the whole teeth surfaces, 88% of decays occur on this site. [1][2] Deep grooves on the occlusal surface are the susceptible sites for bacterial products accumulation such that they are impossible to be completely eliminated. Thus, they are very likely to help progress the initial caries rapidly. Since fluoride therapy was effective on the smooth surfaces, many efforts have been made to provide a physical barrier in form of fissure sealant to separate the occlusal surface from mouth environment and subsequently prevent tooth caries to some extent. [3][4] Fissure sealant was first introduced in the mid-1960s in form of some materials derived from cyanoacrylates family. However, due to the gradual demolition of these compositions by bacteria, they were restricted to be used only in experimental trials and studies. [5] With the introduction of acidic-etched method in 1969 and evolution of resin fissure sealant, these materials acquired special place in dentistry. [3][4][5] By 1971, the first fissure sealant with resin base was marketed by NUVASEAL trademark. [5] Before fissure sealant treatment, etching is performed to make the porosities appear on the enamel and increase the surface energy. During this time, acrylic resin fluid without filler or with micro-filler and low viscosity is applied on the enamel. The resin penetrates into micro pores which are produced by etching to form resin tags [5][6] which in turn, leads to a strong bond between the resin and etched enamel.
Finally, resin is applied to cover all grooves which are susceptible to carries and also to prevent penetration of debris, bacteria, and so on. [1] The clinical success of any kind of pit and fissure sealants is directly linked to their ability to remain bonded to the occlusal pits and fissures. [7] One of the most important reasons of failure of fissure sealant treatment is contamination of enamel surface with saliva. [8][9] In order to reduce the sensitivity to saliva and moisture during treatment, application of hydrophilic dentin bonding material was introduced in 1992. [10] Thereafter, numerous studies reported that application of hydrophilic bonding material increased the fissure sealant retention in case of contamination with saliva. [8][9][10][11] The studies by Perdiago et al., [8] Hebling and Feigal, [9] and Hit and Feigal [10] showed that bonding agent increased the bond strength when applied under the fissure sealant. Askarizadeh et al., [11] in addition to Asselin et al., [12]  seconds between the saliva and etched-enamel would not help diffuse saliva composition and thus would not produce any significant difference in retention and microleakage. [13] There are still controversies over using the conventional methods or the newer methods such as selfetched bonding material. Chasqeira et al., [14] in their in vivo, study concluded that the self-etching adhesive systems (Prompt-L-Pop and Xeno III) produced similar satisfactory shear bond strength values between fissure sealant material and superficial enamel. Highly strong self-etched systems would produce strength equal to acid-etch and rinse methods. However, their highly acidic pH (pH≤1) significantly weakens the bond strength. Moreover, the retention is merely mechanical in this method and acid-etch and rinse method seems to be the best and most effective method to achieve suitable adhesion to teeth surfaces. [14][15] Based on the evidence-based studies, the American Dental Association (ADA) Council on Scientific Affairs announced that self-etch bonding materials that do not include separate stages for etching procedure are not suggested due to their lower adhesion compared to the conventional methods. [16][17]  Blesch's study (2007) represented that using a kind of modern hydrophilic fissure sealant would eliminate the need for bonding application even in case of enamel contamination with saliva. Additionally, it had not seen any change in fissure sealant margin or fissure sealant superficial quality; in fact the need for bonding was purged after etching. [18] The present study assessed a kind of hydrophilic

Materials and Method
In this clinical trial study, 31 patients aged 6-12 years old were selected from those referring to the Department of Pediatric Dentistry at Shiraz Dental School.
The patients had at least a permanent molar tooth on either side of the mandible which was completely erupted. Inclusion criteria for participation in this study were having completely erupted first or second molar mandibular teeth, presence of complicated and deep grooves on the teeth surfaces, absence of occlusal or interproximal caries, being categorized as a low risk patients based on the caries and oral hygiene, and approving the participation and filling the consent form to cooperate with the researchers during the trial periods .As long as the ethics was concerned, the patients were summoned for re-treatment in case of failure of fissure sealant therapy after the end of the study.
The follow-up period was decided to be 6 months with respect to the fissure sealant guidelines and the previous studies. [17][18][19] After selecting the patients, one of the two mandibular permanent molars was randomly selected to be treated with method A, and the other was left to be treated with method B.
In method A, the occlusal surface was rinsed with brush and hand piece (low speed) and after being iso-lated by cotton rolls, the tooth was etched with 35% phosphoric acid (Ultradent; USA) for almost 20 seconds and then rinsed.
The isolation by cotton rolls was adopted respecting the results of previously performed investigations, as well as the pediatric dentistry reference texts that had mentioned performing fissure sealant does not require isolating the teeth by rubber dam, and that isolation by cotton rolls can yield the satisfactory results. In method B, the other tooth was isolated by using cotton rolls. The tooth surface was rinsed and dried by using a micro brush. Similar to method A, the tooth was etched, rinsed and dried. Then, a saliva contaminated micro brush was used to wet the etched enamel.
The tooth was dried so that the sealant could be placed on it. Light-curing was done as in method A. Having assessed the tooth, all cotton rolls were then removed.
The patients were summoned 6 and 12 months later. Two independent blind observers examined the teeth clinically using Feigal's scores (Table 1). [1] Based on this method, the fissure sealant was consid-

Results
The present clinical trial study assessed 31 patients (62 teeth), aged 6 to 12 years (Mean±SD age 8.13±1.77). Restorative material adjacent to the tooth and not detectable with an explorer 1 Margin detectable with the explorer 2 Crevice along the margin of visible width and depth 3 Crevice formation with exposure of central fissure B. Marginal Discoloration 0 No color change at the tooth-sealant interface 1 Discoloration noted along the margin in one area 2 Discoloration noted along the margin in multiple areas 3 Severe discoloration with evidence of penetration and leakage C. Anatomical Form 0 Harmonious and continuous with occlusal form and structure 1 Change in anatomical form but all pits and fissures covered 2a Loss of sealant from one or two pits or accessory grooves (partial loss), but no need to repair or replace sealant 2b Loss of sealant from pits or accessory grooves (partial loss), with a need for replacement or repair of the sealant 3 Loss of sealant from all pits (total loss) 7 Partial loss due to occlusion 9 Bubble (not connected with the margins) The inter-observer agreement test (K=0.713, p= 0.0001) showed that there was an agreement between the two observers.
As represented in Table 2, the rate of success after 6 months was equal in both dry and wet conditions; so there was not any significant difference between them. The results obtained from two of the investigated domains including marginal integrity and marginal discoloration were completely similar (p= 1). In anatomical form, one item was rated higher in wet condition rather than the dry condition; the difference was not statistically significant, though (p= 1).    [21][22] and used flowable composites combined with a total-etch adhesive to seal pits and fissures; however, this method seemed to be as sensitive as using hydrophilic bonding agents with pit and fissure sealants.
Fissure sealant is commonly used in the age range, during which the patient's cooperation is weak and tooth isolation is difficult. So, fissure sealant therapy is suggested to be applied using a rapid easy-touse method with less technical sensitivity. to be 95%. [23] In another study by Baghosion [24] and Manhart et al., [25] the success rate was reported to be 96%; although in the study by Backett et al.,